Propeller for aircraft



A. BRULLE.

PHOPELLER F'OR AIRCRAFT.

APPLICATION FlLED-NOV, as, 1920.

2 SHEETS-SHEET Patented Dec. 6, 1921.

as. lggg INVENTOR.

BY WORNEY.

A. BRULLE.

PROPELLE R FOR AIRCRAFT. APPLICATION FILED NOV. 16. 1920.

1,399,290, Patented Dc. 6,1921.

' 2 SHEETS-SHEET 2.

INVENTOR.

A TTORNE Y.

UNITED STATES ALEXANDER BRULLE, OF NEW YORK, N. Y.

PBOPELLER FOR AIRCRAFT.

Specification of Letters Patent.

Patented Dec. 6, 1921.

Application filed November 16, 1920. Serial No. 424,458.

To all whom it may concern:

Be it known that I, ALEXANDER BRULLE, a citizen of Hungary, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Propellers for Aircraft, of which the following is a full, clear, and exact specification.

This invention relates to propellers for aircraft and has for its object to provide an improved form of spiral or screw propeller for this purpose which will increase the speed of the aircraft equipped therewith.

Another object is to provide a propeller of this type composed of similar sections secured together at their edges to form the spiral blades, each section consisting of a hub section and oppositely extending blade sections, and corresponding generally to the usual form of two-blade propeller now used for driving aircraft. Each section of the spiral propeller is also bowed from the hub to the tips of its oppositely extending blades so as to give the spiral blades a dished formation adapted to densify the air in the spiral pockets between them which gives greater resistance against which the propeller may push and consequently produces greater speed.

The invention will be first hereinafter described in connection with the accompanying drawings, which constitute part of this specification, and then more specifically defined in the claims at the end of the description.

In the accompanying drawings, wherein similar reference characters are used to designate corresponding parts throughout the several views 2-- Figure 1 is a side elevation of a propeller of sectional construction made substantially ill accordance with this invention.

Fig. 2 is an end elevation thereof.

Fig. 3 is a section on the line III-III of Fig. 2 drawn to a larger scale.

Fig. 4 is a section on the line IVIV of Fig. 2 also drawn to the scale of Fig. 3.

Fig. 5 is a detailed view of two sections of the propeller looking at the end of the shaft and showing how said sections are assembled.

Fig. 6 is a side view of the same two sections of the propeller showing the bowed formation thereof, and

Fig. 7 is a side elevation of a modified form of propeller similar to that shown in F ig, l but made in one piece instead of in sections.

As illustrated in Figs. 1 to 6, inclusive, the spiral propeller 1 is preferably made of a plurality of sections 3 each having a hub section 7 and oppositely extending blade sections 6. The hub sections are mounted on a shaft 2, and the blade sections constitute portions of the continuous spiral blade of the whole propeller. Each section 3 as a whole is bowed, as best shown in Fig. 6, the opposite edges 4; and 5, and 8 and 9, respectively, of the oppositely extending blade sections of the same being parallel to each other and fitting along the adjacent edges of the next propeller sections in front and rear thereof along the shaft. Said abutting lateral edges of the propeller sections 3 are fastened together in any suitable and durable manner. The sections may be made of wood and their edges glued together.

The bowed formation of the propeller sections in operation caused the air to be caught in the pockets between the blades to some extent, and as additional air is being continually drawn faster than it is discharged the result is that said air is compressed or densified in its course through said spiral pockets until it is finally discharged. The blades of the propeller are thus provided with increased resistance against which they may push with the result that the speed of the aircraft equipped with the propeller will also be increased.

If desired, the propeller may be cast or otherwise formed in one piece as at 10 in Fig. 7,said propeller having the hub portion 11 extending throughout its length and from which the spiral blades 12 extend in the same bowed or dished formation as in the sectional form of propeller illustrated in the other figures of the drawings. In both forms, the blades are tapered from the hub to the outer edge of the propeller, as shown in Figs. 2, 3 and 4, so as to provide the necessary strength along with the bowed or dished formation which produces the superior results set forth. When the propeller is made of wood, the sectional construction greatly simplifies the production of the proper and true contour of the spiral blades.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. A spiral screw propeller composed of a plurality of similar sections each'having, a hub section and oppositely extending blade sections, said sections being secured together edge to edge to form the continuous spiral screw, and each section being bowed axially of the propeller from the hub portion to the ends of its blade portions for the purpose specified.

2. A spiral screw propeller composed of a plurality of similar sections each having a hub section and oppositely extending blade sections, the lateral edges of the sections being parallel throughout both the hub and blade portions thereof and secured to the adjacent edges of other sections in front and rear of each section to form the con-V tinuous spiral screw, and said lateral edges of each section being curved aatiallyoi? the propeller to givea dish to the blades for the ALEXANDER BRULLE. 

